Torque limiting chuck



March 1941-v A. l. KIRKLAND 2,236,101

TORQUE LIMITING'CHUCK Filed May 31, 1940 3 Sheets-Sheet 1 INVENTOR.

ATTORNEY.

March 25, 1941. A KIRKLAND j Y 49 12 52 32 39 a? 37 INVENTOR.

v k/mzj MM/md BY 4 ATTORNEY.

' TORQUE LIMITING CHUCK 7 Filed May 31 1940 3 Sheets-Sheet a Patented Mar. 25, 1941 UlfllTED STATES PATENT OFFICE 2,236,101 'ronoui': LIMITING cnucx Arthur I. Kirkland, Detroit, Mich, assignmto Detroit Power Screwdriver Company, a corporation of Michigan Application May 31, 1940, Serial No. 337,971

r 7 Claims. The present invention pertains -to a novel chuck through which motion is transmitted from a power shaft to a, driven or work shaft for the purpose of enabling the latter shaft to perform any sortof work for which it may be adapted automatically becomes inoperative when a pre- 5 determined torque is reached.

, The device of the invention comprises essen-' tially a housing in which are mounted a driven clutch element and driving members cooperating with abutments on the element. The driven :0, element has a driving connection with the work shaftand is yieldingly held against the driving members by means of a spring. The tension of i .the spring against the clutch element is regulated by means of an adjustable part of the hous- 25 ing. A power shaft drives the housing, the driving members, the clutch element andthe work shaft. When the torque of the work shaft exceeds the pressure of the spring, the latter yields to permit the driving members to ride over the 30 albutments without imparting motion to the work s aft.

Another object of the invention is to provide a chuck wherein the driving connection between the work shaft and the clutch element is autoample in the following description'and in the accompanying drawings in which:

Figure 1 is avertical section of the device in release or idle position;

Figure 2 is a similar section of the device in en? gaged or operative position:

Figure 3 is a section on the line I ure 1:

matically disengaged when the work shaft is withdrawn from the work, so that the work shaft 3-4 tot Fig-.

Figure-4 is a section on the line 4-4 of Figure 1;

Figure 5 is a section on the line 5--5 of Figure 1;

Figure 6 is a side elevation of the driven clutch 5 disk;

Figure '7 is a section on theline 1-1 of Fig ure 1; I

Figure 8 is an elevation of the driven shaft showing the external spline formed on the upper end thereof;

Figure 9 is a vertical section of a modification, illustrating the release or idle position;

Figure 10 is a similar section showing the engaged or operative position;

Figure 11 is a section on the line H-H of Figure 9;

FigureIZ is a section on the line I2--l2 of Figure 9, and

Figure 13 is a section on the line l3-- l3'of Figure 10.

Reference to these views will now be made by use of like characters which are employed to designate corresponding parts throughout.

In Figures 1 and 2 is shown the lower end of a driving'spindle Ito which is attached a substantially cylindrical housing 2 by any suitable means such as screw threads 3. It will be understood that the power for rotating the spindle I may be applied by any well known or suitable means. 80 On the lower end of the housing 2 is adjustably screwed an inverted cap 4. Other parts, presently to be described, are inserted before the cap is applied, and it will become evident that the assembly is maintained by means of the cap.

In the top of the member 3 are formed a num- I ber of radial grooves 5 exposed to the cavity 5 of the member 2. The grooves receive rollers I which are preferably but not necessarily tapered. The rollers may for convenience be inserted 40 through openings 8 in the side wall of the memher 3- and subsequently closed by screw plugs 9. Assuming that the cap 4 has not yet been applied a driven'clutch disk I! is inserted through the open end of the housing I and moved into contact with the rollers l. The upper surface of this member, as shown. more clearly in Figure 6, is formed with a plurality of slopes or inclines I l extending circumferentially and corresponding in number and in spacing to the rollers I. The 59 lower end of each;slope merges into a stop seat or abutment I! which determines the upper end wof the next slope. The rollers 'I are adapted to engage the abutments l2 and drive the clutch disk II on rotation'of the spindlel and housing F 2 therewith, and the rotation of the clutch disk is transmitted to other parts by the mechanism that will presently be described.

The driven or work shaft l3 which is next .inserted has its upper end formed with an external spline ll adapted to engage an internal spline l5 formed concentrically in the clutch disk iii. In the upper end of the shaft I3 is formed a cavity l6 receiving a coil spring H on which is mounted a pin IS. The latter engages the top of the cavity iii in the housing 2 and serves as an abutment whereby the spring ll disengages the spline connection when there is no downward pressure on the housing 2 or no upward pressure on the shaft i3, as shown in Figure 1. This is the idle position of the device.

A follower IS in the shape of a cup is next inserted in the housing 2 and broughtagaist the bottom of the clutch disk III. In the bottom of the member 19 is fitted a bushing 20 forming a bearing for the shaft l3 and a stop limiting the downward movement of the spline l4 when the latter is withdrawn from spline I5 by the spring II, as in Figure 1. The bottom of the cap 4 is also fitted with a bronze bushing 2| for the shaft l3. A heavy coil spring 22 is next inserted, followed by a baseplate 23, and finally the cap 4 may be fitted with an adapter for this purpose.- 'For example, the shaft may be squared at 26 at its lower end to receive a socket member 2? held by a ball 28 backed by a spring 29 mounted in the member. The member 2! fits on the head of a stud 30 to be driven into a body or may, in like manner, engage a nut or any other piece of work for which it is adapted.

In the subsequent operation, the device, including the drive shaft 8 and housing 2-41, is pushed toward the work until the upper wall of the cavity 3 engages the upper end of the shaft 63 as shown in Figure 2. This movement also engages the splines I l and i5 with each other and forms a driving connection between the clutch disk iii and the shaft l3. At the same time the spring I! is obviously compressed by the inward movement of the pin 88. The rotation of the shaft i and housing 2 brings the rollers ll against the abutments B2 of the clutch disk ill to drive the disk and the shaft i3.

When the work piece 30 has been driven home, the spring 22 will yield if it has previously been adjusted to the proper tension, and the rollers l on striking the abutments l2 will press the clutch disk l0 and ride over the abutments. In so doing the rollers also descend on the slopes II. It will be seen that the latter are'of substantial extent circumferentially, or considerably longer than the diameter of the rollers. Consequently, the rollers descend gradually in approaching the next abutment and thereby eliminate the abrupt drop which is characteristic of other tools and which impart an axial pounding which strains the threads and tires the operator. The first few impacts of the rollers against the abutments at this time will tighten the member 30, and subsequently the rollers will ride more freely over the abutments. .Since this action depends on the tension of the spring 22 asstated above, it. is

evident that the initial adjustment of the spring determines the maximum torque to be applied to the work piece 30, and the spring 22 is of course adjusted accordingly by means of the cap 4. The adjustment is secured by a stud 4' threaded in the cap and receivable in any one of a number of grooves 25' cut at suitable intervals across the threads 25. p

The riding of the rollers over the abutments can be felt by the operator and is a signal to him that the tool should be withdrawn from the work piece. When this is done, the spring H expands and disengages the splines l4, IS with the result that the continued rotation of the shaft l and housing 2 under power is not transmitted to the work shaft i3 when the latter is idle.

Figures 9 to 13 show a modified device operating on substantially the same principle but designed to run with somewhat less bumping when the work piece has been driven home.

As in the other construction, there is a power shaft 3! to which .is attached. a cylindrical housing 32 by any suitable means such as screw threads 33. The top of the cavity 34 is formed with radial grooves 35 in which are mounted rollers 36. The driven clutch member is in the form of an elongated body 3'! formed with'a head 38 at its upper end. Beneath the head is a ring 39 adapted to slide on the narrower part of the body 3? under conditions presently to be described.

A number of holes are formed through the overhanging part of the head and correspond in number and in spacing to the rollers 36. In each hole is slidably mounted a pin it having its upper end pointed as at 2 and normally exposed above the top of the head as shown in Figures 9 and 10 for engagement by one of the rollers 38.

The ring 39 is backed by a rather heavy coil spring 43 resting on a base plate or ring i l.

With this assembly completed, a cap is screwed on the open end of the housing 32, with ball bearings d8 inserted between the ring (it and the with the clutch member 37. A lengthwise groove- SE is formed in the member 59 and receives a pin 52'fixed in the member 37. Consequently the shaft 69 maybe released from the socket till, but not entirely ejected from the cavity fill, by a coil spring 53 surrounding the reduced upper portion of the shaft and bearing against the end wall of the cavity d'l.

The exposed end of the shaft 39 may engage the work directly or may be adapted for this purpose, for example, by means of a socket member 56 mounted on the squared tip 55 of the shaft and held thereon by a spring-pressed ball 56. The socket 51 in the member 5 3 may engage the head of a stud 5B or a nut or other member for which it is adapted.

In the idle condition of the device, the spring 53 disengages the tongue 50 from the socket 48, as in Figure '9. When the work is engaged, the shaft 3i and the housing 32 45 are moved towards the work so that the spring 53 is compressed and the tongue 50 received in the socket 49, as in Figure 10. On rotation of the shaft,the

rollers 36 engage the pointed ends of the pins H and drive the clutch member 31 and with it the roller to depress and ride over the pins 4|, in the driving engagement with said developed in said shaft exceeds the. tension of members override said manner described in connection with Figures ,1

to '7. The initial overriding, however, exerts some lateral force against the pins to tighten the work piece. The overriding can be felt by the operawork. The spring 53 then disengages the shaft 9 from the socket 48 so that this shaft is not driven while the tool is idle with the shaft 3| rotating under power.

Althoughspecific embodiments of the invention have been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as in- -di-cated by the appended claims.

What I claim is:

l. A chuck comprising a rotary housing, a driven clutch member therein and having abutments, driving members propelled by said housing and adapted to engage said abutments, a work shaft having-a sliding connection withsaid clutch member in driving relation therewith, and a spring bearing against said housing and supporting "said clutch member in driving relation with said driving members, said spring being disposed between said clutch member and the working end of said shaft, whereby said driving abutments and shift said member on said driving connection to compress said spring, when the torque developed in said shaft exceeds the tension of said spring.

2. A'chuck comprising a rotary housing, a driven clutch member therein and having abutments, driving members propelled by said housing and adapted to engage said abutmentsya work shaft having asliding connection with said clutch member in driving relation therewith, spring means tending to eject said shaft out of said housing and to withdraw the shaft from clutch member, and a spring bearing against said housing and supporting said clutch member in driving relation with said driving members, said spring being disposed between said clutch'member and the working end of said shaft, whereby said driving members override said abutments and shift said member on said driving connection to com press said spring, when the torque developed in said shaft exceeds the tension of said spring.

3. A chuck comprising a rotary housing, a driven clutch member therein and having abut ments, driving members propelled by said housing and work shaft having a direct sliding connection with said clutch member in driving relation therewith, and a, spring bearingagainst said housing and supporting said clutch member in driving relation with said drivinz members, said and shift said member on said driving connection to compress said spring when the torque said spring.

adapted to engage said abutments, a

. said sliding connection .nection with saidclutch member in driving relation therewith, and a spring. bearing against said housing and supporting said 'clutch member in driving relation with said driving members, said-spring being disposed between said clutch member and the workihg end of said shaft,

' whereby said driving members override said tor, whereupon he withdraws the tool from the abutments and shift said member on said driving connection to compress said spring, when the torque developed in said shaftexceeds the tendriven clutch member therein and having abutments, driving members propelled by said housing and adapted to engage said abutments, a

work shaft having a directsliding connection with said clutch member in driving relation therewith, spring means pending to eject 'said shaft out of said housing and to withdraw the shaft from driving engagement with said clutch member, and a spring bearing against said housing and supporting said clutch member in driving relation with said driving members, said spring being disposed between said clutch member and the working end of said shaft, whereby said driving members override said abutments and shift said member on said driving connection to compress said spring, when the torque developed in said shaft exceeds the tension of said spring.

6. A chuck comprising a rotary housing, a driven clutch member therein and having abutments, radial driving rollers mounted between said housing and clutch member and adapted to engage said abutments, each abutment having a slope extending therefrom in the driving direction, said slopes being engageable by said rollers and having each a length substantially greater than the diameter of said rollers, a work shaft having an axial spline engagement with said clutch member, and a spring mounted in said housing and holding said clutch member against said rollers, whereby said rollers override said abutments and travel on said slopes when the torque developed in said shaft exceeds the tension of said spring. i

'1. A chuckcomprising a rotary housing, a driven clutch member therein and having abutments, radial driving rollers propelled by said housing and adapted to engage said abutments, each abutment having a slope extending therefrom in the driving direction, said slopes being engageable'by said rollers and having each a length substantially greater than the diameter of said rollers, a work shaft having a sliding connection with said clutch member in driving relation therewith, and a spring bearing against said housing and supporting said clutch member-in driving relation with said rollers, said u spring being disposed between said clutch memher and the working end of said shaft, whereby said rollers override said abutments and travel on said slopes, thereby shifting said member on to-compress said spring, when-the torque developed in said shaft exceeds the tension ofsaid spring.

. AR'IHUR I. KIRKLAND. 

